Option 1:- Change SQL Server Password in Management StudioOption 2:- Change SQL Server Password using SQL ScriptOption 3:- Change SQL Server Password with software (No technical expertise required)Since the first two options are already elaborated extensively I restrict myself for the option 3 only. A user with little or no technical knowledge of SQL Database can easily perform the resetting of SQL password without have to worry about data loss. The software is designed keeping simplicity in mind and therefore is a perfect companion for every System Administrator. Extensive knowledge and software description can be gained through the official website. http://www.mssqlserverrecovery.net/sql-password-recovery

The single user mode is less known to SQL Server users. After password forgotten, just start your SQL Server instance in single user mode and it allows you to run the SQLCMD command to reset your login password, or create a new user account. Check out this how-to article for detailed instructions.